Pressure-sensitive recording material

ABSTRACT

A pressure-sensitive and heat-sensitive recording material contains color-forming agents of the formula ##STR1## wherein R 1  denotes hydrogen or a non-ionic radical which is free from amino groups, 
     R 2  denotes hydroxyl, alkylamino, dialkylamino, acylamino, aralkylamino, arylamino, a saturated heterocyclic radical, alkoxy, alkenyloxy, aralkoxy, cycloalkoxy, aryloxy, acyloxy or a direct bond to R 4 , 
     R 3  denotes hydroxyl, alkoxy, aralkoxy, alkenyloxy, cycloalkoxy, aryloxy, alkylthio, arylthio or a radical of the formula ##STR2## wherein R 5  and R 6  independently of one another denote hydrogen, alkyl, aralkyl, cyloalkyl or aryl or, together with the nitrogen atom, form a ring, or  R 5  forms a ring with the ring B in the o-position relative to the nitrogen atom, and 
     R 4  denotes an aryl radical which is free from amino groups or a heterocyclic radical.

The present invention relates to a pressure-sensitive and heat-sensitive recording material which contains colour-forming agents of the formula I ##STR3## In the formula I: R₁ denotes hydrogen or a non-ionic radical which is free from amino groups, R₂ denotes hydroxyl, alkylamino, dialkylamino, acylamino, aralkylamino, arylamino, a saturated heterocyclic radical, alkoxy, alkenyloxy, aralkoxy, cycloalkoxy, aryloxy, acyloxy or a direct bond to R₄, R₃ denotes hydroxyl, alkoxy, aralkoxy, alkenyloxy, cycloalkoxy, aryloxy, alkylthio, arylthio or a radical of the formula ##STR4## wherein R₅ and R₆ independently of one another denote hydrogen, alkyl, aralkyl, cycloalkyl or aryl or, together with the nitrogen atom, form a ring, or R₅ forms a ring with the ring B in the o-position relative to the nitrogen atom, and R₄ denotes an aryl radical which is free from amino groups or a heterocyclic radical denotes. Further rings can be fused to the rings A, B and R₄. The cyclic and acyclic radicals and the rings A and B can contain non-ionic substituents.

By non-ionic substituents there are to be understood, in the sense of the present invention, those substituents which are customary in dyestuff chemistry and do not dissociate under the usual preparation and use conditions, such as halogen, for example fluorine, chlorine and bromine, hydroxyl, alkyl groups, alkenyl radicals with preferably 2-4 C atoms, aralkyl, alkoxy or hydroxyalkoxy, cycloalkoxy, aralkoxy, aryloxyalkoxy, alkylthio, aralkylthio, arylthio, nitro, cyano, formyl, alkylcarbonyl, arylcarbonyloxy, alkylcarbonyloxy, alkoxycarbonyloxy, alkylcarbonylamino, alkylaminocarbonyloxy, alkylsulphonylamino, ureido, N-alkylureido, aryloxycarbonylamino, alkoxycarbonylamino, carbamoyl, N-alkylcarbamoyl, N,N-dialkylcarbamoyl, N-alkyl-N-aryl-carbamoyl, sulphamoyl, N-alkylsulphamoyl, N,N-dialkylsulphamoyl, alkylsulphonyl, alkenylsulphonyl, arylsulphonyl, aralkylsulphonyl, aryloxysulphonyl, aryloxycarbonyl, alkoxycarbonyl, mono- di- or trialkylsulphamidine, alkylarylsulphamidine or alkylcycloalkylsulphamidine, preferably 1-4 C atoms being present in the alkyl radicals mentioned. Preferred aryl is phenyl, preferred aralkyl is benzyl and preferred cycloalkyl is cyclohexyl.

The alkyl radicals mentioned in the case of formula (I) are in general those with 1-6 C atoms. The alkyl radicals mentioned under R₂ can have up to 12 C atoms. Examples of non-ionic substituents of the alkyl radicals are halogen, hydroxyl, C₁ -C₄ -alkoxy, phenyloxy, benzyloxy, C₁ -C₄ -alkylcarbonyloxy, C₁ -C₄ -alkoxycarbonyl, amidocarbonyl or cyano.

Examples of preferred alkenyl radicals are C₂ -C₅ -alkenyl radicals.

Aryl is preferably understood as phenyl or naphthyl and aralkyl is understood as benzyl and β-phenyl-C₁ -C₄ -alkyl. The phenyl rings can be substituted by, for example, 1-4 non-ionic radicals, such as halogen, C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, C₁ -C₄ -alkoxycarbonyl, amidocarbonyl, cyano, amidosulphonyl, C₁ -C₃ -alkylcarbonylamino or benzoylamino.

Cycloalkyl represents, in particular, cyclopentyl and cyclohexyl, which can be substituted, for example, by 1-4 non-ionic radicals, in particular methyl.

Acyl preferably represents acetyl, propionyl, benzoyl, toluyl, C₁ -C₂ -alkylsulphonyl or phenylsulphonyl.

Examples of saturated heterocyclic radicals R₂ are, for example, morpholino, piperidino and pyrrolidino.

Examples of suitable heterocyclic radicals R₄ are the indole, triazole, furane, thiophene, pyridine, pyrazolone, thiazine, oxazine, benzothiophene, indazole, benzothiazole, quinoline, phenothiazine and phenoxazine radical.

R₅ and R₆, together with the nitrogen atom, can form, for example, a 5-membered or 6-membered heterocyclic ring, such as pyrrolidine, pyrazoline, piperidine or morpholine. R₅, together with ring B, can form, for example, an indoline or tetrahydroquinoline ring. The abovementioned rings can be substituted by methyl groups or phenyl groups.

The rings A and B can be substituted by 1-4 further non-ionic substituents, such as C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen, in addition to the radicals R₁ and R₃.

By halogen there is understood, in particular, fluorine, chlorine and bromine.

A possible ring to which A and B can be fused is, in particular, the benzene ring.

In formula (I), R₃ preferably represents ##STR5## when R₄ denotes aryl.

Preferred colour-forming agents of the formula (I) correspond to the formula ##STR6## wherein R₁ ' denotes hydrogen; hydroxyl; C₁ -C₆ -alkoxy; C₂ -C₆ -alkenyloxy; cyclohexyloxy; cyclopentyloxy; benzyloxy, phenylethoxy, phenyloxy, naphthyloxy, phenylthio or naphthylthio which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; or C₁ -C₆ -alkylthio,

R₂ ' denotes hydroxyl; C₁ -C₁₂ -alkyl- or dialkylamino; C₁ -C₄ -alkylcarbonylamino; benzylamino phenylethylamino, phenylamino, naphthylamino, phenylsulphonylamino or benzoylamino which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; morpholino, piperidino or pyrrolidino which are optionally substituted by C₁ -C₄ -alkyl; C₁ -C₁₂ -alkoxy; C₂ -C₁₂ -alkenyloxy; C₁ -C₄ -alkoxycarbonyloxy; benzyloxy, phenylethoxy, phenyloxy, naphthyloxy, benzoyloxy, phenylsulphonyloxy or phenylsulphinyloxy which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; cyclohexyloxy; cyclopentyloxy or a direct bond to R₄ ', R₃ ' denotes hydroxyl; C₁ -C₆ -alkoxy; C₂ -C₆ -alkenyloxy, cyclohexyloxy; cyclopentyloxy; benzyloxy, phenylethoxy, phenyloxy, naphthyloxy, phenylthio or naphthylthio which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; C₁ -C₆ -alkylthio or a radical of the formula ##STR7## R₅ ' and R₆ ' independently of one another denote hydrogen; C₁ -C₆ -alkyl which is optionally substituted by C₁ -C₄ -alkoxy, C₁ -C₄ -alkylcarbonyloxy, hydroxyl, halogen or cyano; benzyl, phenylethyl, phenyl or naphthyl which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; cyclopentyl or cyclohexyl, or

R₅ ' and R₆ ', together with the nitrogen atom, denote a pyrrolidine, pyrazoline, piperidine or morpholine ring, or

R₅ ', together with the nitrogen atom and ring B, denotes an indoline or tetrahydroquinoline ring, it being possible for the rings mentioned to be substituted by methyl or phenyl,

R₄ ' denotes a radical of the formula ##STR8## in which m=1-4 and

R₈ =hydrogen, C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy; halogen; carboxamide, sulphonamide; cyano; nitro; halogen; C₁ -C₄ -alkylthio; C₁ -C₄ -alkylsulphonyl; C₁ -C₄ -alkylcarbonyl; C₁ -C₄ -alkoxycarbonyl; or benzyl, phenylethyl, benzyloxy, phenylethoxy, phenyloxy, cyclopentyloxy, cyclohexyloxy, phenylthio, benzylsulphonyl, phenylethylsulphonyl or phenylsulphonyl which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen, or R₄ ' denotes an indole, triazole, furane, thiophene, pyridine, pyrazolone, thiazine, oxazine, benzothiophene, indazole, benzothiazole, quinoline, phenothiazine and phenoxazine radical, which in turn can be substituted by 1-2 radicals, such as C₁ -C₆ -alkyl, phenyl, benzyl or C₁ -C₄ -alkoxy which are optionally substituted by C₁ -C₄ -alkoxy, cyano or halogen,

R₇ and R₇ ' denote hydrogen, C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, halogen or nitro and n and n' denote 1-4, and

wherein

the rings A and B can be fused, in the 2,3-position, to a benzene ring. Of the colour-forming agents of the formula II, those of the formula ##STR9## wherein R₁ " represents hydroxyl; C₁ -C₄ -alkoxy; C₁ -C₄ -alkylthio; cyclohexyloxy; cyclopentyloxy; or benzyloxy, phenylethoxy, phenyloxy, naphthyloxy, phenylthio or naphthylthio which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen,

R₄ " represents a radical of the formula ##STR10## and the remaining symbols have the meaning as in the case of formula II, are of importance.

Of these colour-forming agents, those of the formula ##STR11## wherein R₅ " and R₆ " independently of one another denotes hydrogen; C₁ -C₄ -alkyl; cyanoethyl; hydroxyethyl; acetoxyethyl; C₁ -C₄ -alkoxyethyl; or benzyl or phenyl which are optionally substituted by methyl, ethyl, methoxy or ethoxy, or

R₅ " and R₆ ", together with the nitrogen atom, form a pyrrolidine, piperidine, morpholine, pyrazoline or piperazine ring which is optionally substituted by methyl and/or phenyl,

R₉ and R₉ ' represents hydrogen, methyl, ethyl, methoxy, ethoxy or chlorine, or

R₅ " and R₉ ', together with ring B and the nitrogen atom, form an indoline or tetrahydroquinoline ring which is optionally substituted by C₁ -C₄ -alkyl, and the remaining symbols have the meaning indicated in the case of the formulae II and III, may in turn be mentioned.

In very particularly preferred examples of the formula IV, R₁ " represents methoxy or ethoxy.

The colour-forming agents of the formula ##STR12## wherein R₁₃ represents C₁ -C₄ -alkyl or phenyl and R₁₄ represents hydrogen; C₁ -C₂₂ -alkyl which is optionally substituted by cyano, chlorine or hydroxyl; C₂ -C₄ -alkenyl; cyclohexyl; or phenyl or benzyl which are optionally substituted by methyl, ethyl, methoxy, ethoxy or chlorine, and

wherein

the remaining symbols have the meaning indicated in the case of the formulae II and IV, are likewise of particular importance.

Of these colour-forming agents, those in which the radical R'₃ represents the formula ##STR13## are preferred.

The colour-forming agents of the formula ##STR14## wherein R₁₃ ' represents methyl, ethyl or phenyl and

R₁₄ ' represents hydrogen or C₁ -C₄ -alkyl, and wherein

the remaining symbols have the meaning as in the case of formulae II and V,

are of very particular interest.

Colour-forming agents of the formula ##STR15## wherein the symbols have the same meaning as in the case of the formulae II, IV and V, are also valuable.

Colour-forming agents of the formula ##STR16## wherein the symbols have the same meaning as in the case of the formulae II, V and VI, are particularly interesting.

In the most important examples of the formula VI and VIII, R₈ represents methyl, hydrogen, phenoxy, benzyloxy, C₂ -C₄ -alkoxy or, very particularly preferably, methoxy.

Preferred radicals R₂ ' in the formulae II-VI are hydroxy, --OR₁₀, ##STR17## morpholino, piperidino and pyrrolidino, wherein

R₁₀ denotes C₁ -C₁₂ -alkyl, benzyl, phenylethyl, cyclohexyl, pheny, tolyl or benzoyl,

R₁₁ denotes hydrogen, methyl or ethyl, and

R₁₂ denotes C₁ -C₁₂ -alkyl, benzyl, phenyl, tolyl, cyclohexyl, acetyl, benzoyl or phenylsulphonyl.

The carbinol bases and derivatives of the formula I are known, or they can be prepared by known processes. However, they represent a new group of colour-forming agents for pressure-sensitive and heat-sensitive recording materials. The carbinol bases are either synthesised direct or liberated from the corresponding colour salts. Suitable colour salts and processes for their preparation are described, for example, in German Auslegeschriften (German Published Specifications Nos.) 1,569,748, 1,569,751, 1,569,742 and 1,811,337 and German Offenlegungsschriften (German Published Specifications Nos.) 1,811,338, 1,811,651 and 1,811,652. The carbinol base derivatives are obtained by procedures such as are mentioned, for example, in Ber. 33, 3357; Zeitschrift fur Farben and Textilchemie 1, 2; Ber. 37, 2867; J. pr. Chem. (2) 118, 118; Ber. 45, 2918, British Patent Specifications Nos. 788,427, 804,087 and 831,852, U.S. Pat. No. 3,488,207, OS (Published Specification) 2,110,518 and Japanese Patent Publications 7,023,833 and 7,009,621.

If the compounds of the I, which are usually colourless or, in the case of the products VII and VIII, are slightly coloured, are brought into contact with an acid developer, they produce orange-coloured, red, blue or green-grey to black colour shades, which are outstandingly fast to light, with a high speed of development.

They can be used individually or in mixtures, and also advantageously in mixtures with other known colour-forming agents. The practical interest of these new colour-forming agents is based, above all, on the possibility of also obtaining uniform navy blue and black shades.

The colour-forming agents of the formula I are used, according to the invention, in pressure-sensitive or heat-sensitive copying materials or documenting materials in the manner technically customary for other known colour-forming agents.

Thus, for example, a pressure-sensitive recording material consists of a donor sheet which contains, or carries in the form of a layer, at least one colour-forming agent of the formula I, dissolved or dispersed in a non-volatile organic solvent, and a receiving sheet which contains, or carries in the form of a layer, acid developer substances of a known type, which can be, for example, inorganic substances, such as clays, metal salts or metal oxides, or organic polymers, such as phenolic resins.

In order to prevent premature reaction between the colour-forming agents and the developer substance, the two components are separated from one another by customary processes, for example by micro-encapsulating the colour-forming agent solution or dispersion.

Processes for the production of microcapsules of this type, which can be crushed by pressure, are known. The colour-forming agent released, at the point at which pressure is applied, on crushing (for example by writing) produces a coloured image on the receiving sheet.

Examples of suitable non-volatile solvents are partially hydrogenated terphenyl, alkylated naphthalenes or dibutyl phthalate. It is also possible, for example, to incorporate the microcapsules and the acid developer substance in a single sheet or in different layers on a single sheet. In heat-sensitive recording systems, the colour-forming agents of the formula I are appropriately fixed in the customary manner in a binder in solution or in dispersion, which softens or melts under the influence of heat, for example by the action of a laser or a heated pen, so that the colour-forming agents come into contact with the acid developer substance and produce the coloured image.

It is possible to incorporate the binder phase and developer phase either in one layer or in different layers on the recording sheet.

Examples of suitable acid developer substances in this case are also crystalline, low-melting organic acids, in addition to the abovementioned Lewis acids.

The processes and formulations described are known, for example, from U.S. Pat. Nos. 2,948,753, 3,096,189 and 3,193,404 and from German Offenlegungsschriften (German Published Specifications) 2,555,080 and 2,700,937.

EXAMPLE 1

A solution of 100 g of the dyestuff of the formula ##STR18## in 250 ml of methanol is allowed to run into a solution of 12.2 g of sodium methylate in 500 ml of methanol at room temperature.

80 g of the carbinol ether of the formula ##STR19## separate out as a yellowish oil. The methanol is separated off from the oily phase and the carbinol ether is dried in vacuo. If a solution of the carbinol ether in ligroin comes into contact with silica gel, the silica gel becomes blue-red in colour.

EXAMPLE 2

A solution of 100 g of the dyestuff of the formula ##STR20## is allowed to run into a solution of 75 g of sodium methylate in 1 liter of methanol. The methyl ether of the formula ##STR21## thereby crystallises out. It is filtered off and boiled up with methylcyclohexane, and is thereby obtained as a colourless crystalline powder.

If a solution of the carbinol ether in toluene is brought into contact with silica gel, the silica gel becomes dark blue in colour.

EXAMPLE 3

A melt consisting of 100 g of 4-dimethylamino-4'-methoxybenzophenone, 75.7 g of 2-phenylindole and 175 g of phosphorus oxychloride is kept at 100° C. for 8 hours, the mixture is then diluted with 250 ml of toluene and this solution is stirred into a mixture of 680 g of 45% strength sodium hydroxide solution and 150 ml of toluene. Ice is thereby continuously added in an amount such that a temperature of 60° C. is maintained in the hydrolysis mixture. The mixture is stirred at 60° C. for 2 hours and the organic layer is separated off and washed with hot water. On cooling, the carbinol base of the formula ##STR22## crystallises out. On contact with silica gel, a solution of the base in ligroin produces an intense black coloration.

The colour-forming agents given in the table which follows can be prepared in the manner indicated in Example 1 and 2.

    __________________________________________________________________________      ##STR23##                                                                                                                Colour shade on con-                R.sub.1                                                                             R.sub.7 R.sub.5   R.sub.6 R.sub.14                                                                             R.sub.15                                                                             tact with silica                    __________________________________________________________________________                                                gel                                 OCH.sub.3                                                                           4-OCH.sub.3                                                                            CH.sub.3  CH.sub.3                                                                               H     H     red                                 "    H       C.sub.2 H.sub.5                                                                          C.sub.2 H.sub.5                                                                        2-OCH.sub.3                                                                          "     "                                   "    "       CH.sub.3  C.sub.2 H.sub.4 CN                                                                     H     "     blue-red                            "    "       C.sub.2 H.sub.5                                                                          C.sub.2 H.sub.4 Cl                                                                     "     "     "                                   "    "       "         CH.sub.2C.sub.6 H.sub.5                                                                "     "     "                                   "    "       "          C.sub.2 H.sub.5                                                                       "     2-OCH.sub.3                                                                          brown-red                           "    "       CH.sub.3  CH.sub.3                                                                               "     3-CH.sub.3                                                                           red-blue                            "    "       C.sub.4 H.sub.9                                                                          C.sub.2 H.sub.4 Cl                                                                     "     H     violet                              "    "       CH.sub.3  CH.sub.3                                                                               "     2,3-benzo                                                                            blue-red                            "    "       "         C.sub.6 H.sub.5                                                                        "     H     blue-violet                         OCH.sub.3                                                                           H       CH.sub.3  H       H     CH.sub.3                                                                             red                                 "    "                                                                                       ##STR24##                                                                               "       "     "     "                                   OC.sub.2 H.sub.5                                                                    "       C.sub.2 H.sub.4 CN                                                                       "       "     OC.sub.2 H.sub.5                                                                     violet                              OC.sub.6 H.sub.5                                                                    "       CH.sub.3                                                                                  ##STR25##                                                                             "     "     "                                   OCH.sub.3                                                                           "       "         CH.sub.3                                                                               2-CH.sub.3                                                                           2-CH.sub.3                                                                           red-violet                          OC.sub.4 H.sub.5                                                                    "       C.sub.3 H.sub.7                                                                          C.sub.3 H.sub.7                                                                        "     H     red                                 OCH.sub.3                                                                           2-Cl    CH.sub.3  C.sub.6 H.sub.5                                                                        H     "     violet                              "    4-Cl    "         CH.sub.3                                                                               "     "     blue-red                            OCH.sub.3                                                                           2-CH.sub.3                                                                             C.sub.4 H.sub.9                                                                          H       H     H     yellow-red                          OC.sub.3 H.sub.7                                                                    H       C.sub.2 H.sub.5                                                                          C.sub.2 H.sub.5                                                                        "     2-C.sub.2 H.sub.5                                                                    "                                   o-i-C.sub.3 H.sub.7                                                                 2-CH.sub.3                                                                             CH.sub.3  H       "     CH.sub.3                                                                             orange                              OCH.sub.3                                                                           3-CH.sub.3                                                                             C.sub.2 H.sub.4 CN                                                                       "       "     6-CH.sub.3                                                                           violet                              "    2,4-di-CH.sub.3                                                                         ##STR26##                                                                               "       "     H     red                                 "    3,4-di-CH.sub.3                                                                        C.sub.2 H.sub.4 CN                                                                       "       2-CH.sub.3                                                                           "     violet                              "    2,5-di-CH.sub.3                                                                        CH.sub.3  C.sub.6 H.sub.5                                                                        H     "     "                                   "    2,4,5-tri-CH.sub.3                                                                     C.sub.2 H.sub.5                                                                          C.sub.2 H.sub.5                                                                        "     "     red                                 OCH.sub.3                                                                           4-tert-C.sub.4 H.sub.9                                                                 CH.sub.3  CH.sub.3                                                                               H     H     blue-red                            "    2-Cl    "         "       2-CH.sub.3                                                                           "     red                                 "    2-CH.sub.3                                                                             "         "       "     "     "                                   "    4-Cl    C.sub.2 H.sub.5                                                                          C.sub.2 H.sub.4 Cl                                                                     2-OCH.sub.3                                                                          "     blue-red                            "    4-OC.sub.6 H.sub.5                                                                     C.sub.3 H.sub.7                                                                          C.sub.3 H.sub.7                                                                        H     "     "                                   "    2-OCH.sub.3                                                                            C.sub.4 H.sub.9                                                                          C.sub.4 H.sub.9                                                                        "     "     "                                   "    4-OC.sub.2 H.sub.5                                                                     CH.sub.3  C.sub.2 H.sub.5                                                                        "     "     "                                   "    4-OC.sub.3 H.sub.7                                                                     C.sub.4 H.sub.9                                                                          C.sub.4 H.sub.9                                                                        "     "     "                                   "    2-OCH.sub.3                                                                            CH.sub.3  CH.sub.3                                                                               3-Cl  "     red                                 "    "       "         "       2-CH.sub.3                                                                           "     red                                 "    3-CH.sub.3                                                                             "         C.sub.2 H.sub.4 CN                                                                     2-OCH.sub.3                                                                          "     violet                              "    5-CH.sub.3 -2-OCH.sub.3                                                                C.sub.2 H.sub.5                                                                          C.sub.2 H.sub.5                                                                        H     "     blue-red                            "    2-OCH.sub.3 -4,6-                                                                      C.sub.3 H.sub. 7                                                                         C.sub.3 H.sub.7                                                                        "     "     claret                                   di-CH.sub.3                                                               "    3-OCH.sub.3                                                                            CH.sub.2 C.sub.6 H.sub.5                                                                 CH.sub.2 C.sub.6 H.sub.5                                                               "     "     violet                              C.sub.3 H.sub.7                                                                     "       i-C.sub.3 H.sub.7                                                                        i-C.sub.3 H.sub.7                                                                      "     "     red                                 OCH.sub.3                                                                           2,5-di-OCH.sub.3                                                                       C.sub.4 H.sub.9                                                                          C.sub.4 H.sub.9                                                                        H     H     red-violet                          "    3-OCH.sub.3                                                                            C.sub.2 H.sub.5                                                                          C.sub.2 H.sub.5                                                                        3-OCH.sub.3                                                                          "     blue-red                            "    2-OCH.sub.3                                                                            "         "       2,3-benzo                                                                            "     red-violet                          "    4-OCH.sub.3                                                                            CH.sub.3  p-C.sub.6 H.sub.4 OC.sub.2 H.sub.5                                                     H     "     red-blue                            "    "       "         CH.sub.3                                                                               "     2-Cl  Corinth blue                        "    "       C.sub.2 H.sub.5                                                                          C.sub.2 H.sub.5                                                                        "     "     violet-grey                         "    "       "         CH.sub.2 C.sub.6 H.sub.5                                                               "     2-CH.sub.3                                                                           Corinth blue                        OC.sub.2 H.sub.5                                                                    4-OC.sub.2 H.sub.5                                                                     CH.sub.3  C.sub.6 H.sub.5                                                                        "     H     claret                              OCH.sub.3                                                                           4-OCH.sub.3                                                                            "         "       2-Cl  "     violet                              "    4-OCH.sub.3                                                                            C.sub.2 H.sub.4 OCH.sub.3                                                                C.sub.2 H.sub.4 OCH.sub.3                                                              2-CH.sub.3                                                                           "     blue-red                            "    "       CH.sub.3  C.sub.2 H.sub.4 OH                                                                     3-CH.sub.3                                                                           "     "                                   "    4-OCH.sub.3 -3-CH.sub.3                                                                C.sub.3 H.sub.7                                                                          C.sub.3 H.sub.7                                                                        "     "     claret                              "    4-OCH.sub.3                                                                            C.sub.4 H.sub.9                                                                          C.sub.4 H.sub.9                                                                        3,5-di-CH.sub.3                                                                      "     blue-red                            "    "       CH.sub.3  C.sub.6 H.sub.5                                                                        2-OCH.sub.3                                                                          "     violet                              "    4-SCH.sub.3                                                                            C.sub.4 H.sub.9                                                                          C.sub.4 H.sub.9                                                                        H     "     claret                              OC.sub.2 H.sub.5                                                                    4-SC.sub.2 H.sub.5                                                                     H         i-C.sub.3 H.sub.7                                                                      "     "     blue-red                            __________________________________________________________________________

    __________________________________________________________________________      R.sub.1                                                                             R.sub.7                                                                               R.sub.14                                                                            ##STR27##                                                    __________________________________________________________________________     OCH.sub.3                                                                           H      H    N-phenylmorpholine                                                                            ruby                                           "    "      "    1,2,3,3-tetramethylindoline                                                                   red                                            "    "      "    1-chloroacetyl-2-methylindoline                                                               red                                            "    "      "    1-phenyl-3-methylpyrazoline                                                                   violet                                         "    "      "    1,3-diphenylpyrazoline                                                                        red-blue                                       "    2-CH.sub.3                                                                            "       "           red-blue                                       "    H      2-OCH.sub.3                                                                            "           dark blue                                      "    "      2-CH.sub.3                                                                             "           red-blue                                       OC.sub.4 H.sub.9                                                                    2-CH.sub.3                                                                            H       "           blue-violet                                    OC.sub.2 H.sub.5                                                                    3-CH.sub.3                                                                            "    N-phenylmorpholine                                                                            violet                                         "    "      "    1,3-diphenylpyrazoline                                                                        red-blue                                       OCH.sub.3                                                                           2,4,5-tri-CH.sub.3                                                                    "    1,2-dimethylindoline                                                                          red                                            "    4-OCH.sub.3                                                                           "    1,3-diphenylpyrazoline                                                                        dark blue                                      "    "      "    1-phenyl-3-methylpyrazoline                                                                   Corinth blue                                   OCH.sub.3                                                                           4-OCH.sub.3                                                                           H    N-phenylmorpholine                                                                            claret                                         "    2-OCH.sub.3                                                                           "    1,3-diphenylpyrazoline                                                                        red-blue                                       "    4-.sub.3                                                                              "       "           greenish-tinged                                                                dark blue                                      "    "      "    1-phenyl-3-methylpyrazoline                                                                   Corinth blue                                   "    "      "    1-methyl-tetrahydroquinoline                                                                  red-blue                                       __________________________________________________________________________

    __________________________________________________________________________      ##STR28##                                                                                                                     Colour shade                                                                   on contact                     R.sub.1                                                                             R.sub.14                                                                            R.sub.5 R.sub.6 R.sub.15                                                                            R.sub.9                                                                             R.sub.10                                                                              R.sub.16                                                                            with silica                    __________________________________________________________________________                                                     gel                            H    H    CH.sub.3                                                                               C.sub.6 H.sub.5                                                                        H    C.sub.6 H.sub.5                                                                     CH.sub.3                                                                              H    green                          "    "    "       "       "    CH.sub.3                                                                            H      "    blue                           "    "    "       "       "    C.sub.6 H.sub.5                                                                     CH.sub.3                                                                              5-OCH.sub.3                                                                         blue-green                     "    "    "       "       "    CH.sub.3                                                                            C.sub.2 H.sub.5                                                                       6-CH.sub.3                                                                          blue green                     "    "    "       "       "    C.sub.6 H.sub.5                                                                     C.sub.2 H.sub.4 CN                                                                    H    blue green                     "    "    "       CH.sub.3                                                                               "    "    CH.sub.3                                                                              "    blue                           "    "    "       "       "    CH.sub.3                                                                            "      "    blue-violet                    "    "    C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                        "    C.sub.6 H.sub.5                                                                     H      "    green-blue                     CH.sub.3                                                                            "    CH.sub.3                                                                               CH.sub.3                                                                               "    CH.sub.3                                                                            CH.sub.3                                                                              "    violet                         H    3-Cl "       "       "    C.sub.6 H.sub.5                                                                     "      "    blue                           H    2-Cl C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                        H    C.sub.6 H.sub.5                                                                     CH.sub.3                                                                              H    blue                           "    3-Cl "       "       "    "    "      "    green-blue                     CH.sub.3                                                                            H    CH.sub.3                                                                               CH.sub.3                                                                               "    CH.sub.3                                                                            H      "    claret                         H    2,5-di-Cl                                                                           "       "       "    C.sub.6 H.sub.5                                                                     "      "    blue                           NO.sub.2                                                                            3-CH.sub.3                                                                          "       "       "    "    CH.sub.3                                                                              "    blue-green                     H    H    C.sub.2 H.sub.4 CN                                                                     "       "    "    "      "    blue                           CH.sub.3                                                                            "    p-C.sub.6 H.sub.4 OC.sub.2 H.sub.5                                                     "       "    CH.sub.3                                                                            "      "    blue                           H    3-Cl "       "       "    C.sub.6 H.sub.5                                                                     "      "    blue-green                     OCH.sub.3                                                                           H    CH.sub.3                                                                               "       "    "    H      "    black                          CH.sub.3                                                                            H    C.sub.6 H.sub.5                                                                        CH.sub.3                                                                               H    CH.sub.3                                                                            CH.sub.3                                                                              H    blue                           H    3-CH.sub.3                                                                          C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                        "    C.sub.6 H.sub.5                                                                     H      "    blue-green                     CH.sub.3                                                                            3-NO.sub.2                                                                          CH.sub.3                                                                               CH.sub.3                                                                               "    CH.sub.3                                                                            "      "    dark blue                      H    H    C.sub.3 H.sub.7                                                                        C.sub.3 H.sub.7                                                                        "    "    CH.sub.3                                                                              "    red-blue                       "    "    C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                        "    "    C.sub.2 H.sub.5                                                                       "    red-blue                       "    2,3-benzo                                                                           CH.sub.3                                                                               CH.sub.3                                                                               "    C.sub.6 H.sub.5                                                                     CH.sub.3                                                                              "    grey                           "    H    C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                        "    CH.sub.3                                                                            C.sub.2 H.sub.4 CN                                                                    "    reddish-tinged                                                                 dark blue                      H    H    C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                        H    C.sub.6 H.sub.5                                                                     C.sub.2 H.sub.4 CN                                                                    H    dark blue                      "    "    "       "       "    "    C.sub.2 H.sub.5                                                                       7-Cl blue-grey                      "    "    "       "       "    "                                                                                    ##STR29##                                                                            H    green-blue                     "    "    "       "       "    "    CH.sub.2 C.sub.6 H.sub.5                                                              "    grey-green                     "    "    CH.sub.3                                                                               CH.sub.3                                                                               3-Br CH.sub.3                                                                            CH.sub.3                                                                              "    red-violet                     "    "    "       "       2-CH.sub.3                                                                          "    "      "    green-blue                     "    "    H       H       H    "    "      "    blue-red                       "    "    CH.sub.3                                                                               C.sub.2 H.sub.4 Cl                                                                     2-CH.sub.3                                                                          "    "      "    red-blue                       "    "    "                                                                                       ##STR30##                                                                             "    "    "      "    blue                           "    "    C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                        2-OC.sub.2 H.sub.5                                                                  "    "      "    red-blue                       CH.sub.3                                                                            "    "                                                                                       ##STR31##                                                                             H    "    "      "    violet                         H    "    "       "       "    "    "      "    red-blue                       "    "    C.sub.6 H.sub.5                                                                        CH.sub.3                                                                               2,3-benzo                                                                           C.sub.6 H.sub.5                                                                     "      "    blue-green                     "    2-OCH.sub.3                                                                         C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                        H    CH.sub.3                                                                            "      "    blue -" 2-CH.sub.3 " " " C                                                     .sub.6 H.sub.5 " " blue        H    3-OCH.sub.3                                                                         CH.sub.3                                                                               C.sub.6 H.sub.5                                                                        H    CH.sub.3                                                                            CH.sub.3                                                                              H    blue                           C.sub.6 H.sub.5                                                                     H    "       "       "    "    "      "    grey                           H    "    H       2-C.sub.6 H.sub.4 CH.sub.3                                                             "    C.sub.6 H.sub.5                                                                     "      "    green                          OCH.sub.3                                                                           "    CH.sub.3                                                                               CH.sub.3                                                                               "    CH.sub.3                                                                            "      "    claret                         "    "    "       "       "    C.sub.6 H.sub.5                                                                     "      "    grey                           "    "    C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                        "    CH.sub.3                                                                            "      "    claret                         "    "    "       "       "    C.sub.6 H.sub.5                                                                     "      "    grey-green -" " 4-C.sub.6                                                      H.sub. 4 OC.sub.2                                                              H.sub.5 CH.sub.3 " CH.sub.                                                     3 " " grey                     "    "    C.sub.6 H.sub.5                                                                        "       "    "    "      "    grey-brown                     "    "    "       "       "    C.sub.6 H.sub.5                                                                     "      "    green-grey                     "    "    C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                        "    CH.sub.3                                                                            H      "    red-brown                      "    "    "       "       "    C.sub.6 H.sub.5                                                                     "      "    grey                           "    "    CH.sub.3                                                                               C.sub.6 H.sub.5                                                                        "    CH.sub.3                                                                            "      "    claret                         "    "    "       "       "    C.sub.6 H.sub.5                                                                     "      "    grey                           "    "    "       CH.sub.3                                                                               "    "    C.sub.2 H.sub.4 CN                                                                    "    claret                         H    H    H       H       H    CH.sub.3                                                                            C.sub.2 H.sub.5                                                                       H    claret                                   .BHorizBrace.                                                        "    "    Phenylmorpholine      C.sub.6 H.sub.5                                                                    CH.sub.3                                                                              "    blue-green                     "    "    "                    CH.sub.3                                                                            "      "    red-blue                       OCH.sub.3                                                                           "    "                    C.sub.6 H.sub.5                                                                     "      "    grey                           H    "    1-Phenyl-4-hydroxyethyl-                                                                            "    "      "    green-blue                               piperazine                                                           "    "    Piperidine           "    "      "    green-blue                     "    "    1,2,3,3-Tetramethylindoline                                                                         "    "      "    red-blue                       "    "    1-Chlorethyl-2-methylindo-                                                                          "    "      "    red-blue                                 line                                                                 __________________________________________________________________________

    __________________________________________________________________________      ##STR32##                                                                                                      Colour                                                                         shade on                                                                       contact                                                                        with                                          R.sub.1                                                                             R.sub.14                                                                          R.sub.3                                                                             R.sub.15                                                                            R.sub.9                                                                             R.sub.10                                                                            R.sub.16                                                                            silica gel                                    __________________________________________________________________________     SCH.sub.3                                                                           H  OCH.sub.3                                                                           H    C.sub.6 H.sub.5                                                                     C.sub.2 H.sub.5                                                                     6-CH.sub.3                                                                          claret                                        SC.sub.2 H.sub.5                                                                    "  "    "    CH.sub.3                                                                            H    H    yellow-red                                    OCH.sub.3                                                                           "  "    "    C.sub.6 H.sub.5                                                                     CH.sub.3                                                                            "    yellow-red                                    __________________________________________________________________________

If the process is carried out in the manner indicated in Example 3, instead of the examples indicated in Examples 1 and 2 and in the tables on pages 14-25, the corresponding products of the formulae ##STR33## are obtained, and, in the case where R₁₀ =H, the colour-forming agents ##STR34## are already obtained during the preparation, H₂ O being split off.

On silica gel, the colour-forming agents of the formulae A, B, C, D and E thus prepared develop the same colour shade as is indicated in the above examples in the case of the corresponding carbinol bases.

EXAMPLE 4

2 g of the colour-forming agent described in Example 1 are dissolved in 48 g of chlorinated biphenyl at 60°-70° C.

7.5 g of pigskin gelatine are dissolved in 60 g of distilled water at 60°-70° C.

The colour-forming agent solution, cooled to about 50° C., is emulsified in the latter solution at about 50° C., during which an oil droplet size of 1-10 μm diameter must be achieved. The resulting emulsion is slowly added to a solution, warmed to about 40° C., of 7.5 g of gum arabic in 60 g of water at about 40° C., whilst stirring. The pH value is adjusted to about 7 with 10% strength NaOH. The mixture is then slowly diluted with 190 g of distilled water having a temperature of 35°-40° C.

Thereafter, 50 g of a 2% strength aqueous solution of Mowiol 26/88 (polyvinyl alcohol from Hoeschst AG) is added to the mixture in the range from 30°-35° C. The pH value is then adjusted to 5.2 by adding aqueous 10% strength acetic acid dropwise, and coacervation is thus started. The mixture is allowed to cool to about 20° C. in the course of 30-45 minutes, whilst stirring continuously. At this point in time, the success of the coacervation can be easily examined microscopically.

The mixture is then cooled to 5°-10° C., 5 g of glutardialdehyde are added in the weakly acid pH range and the hardening is allowed to continue for several hours, whilst stirring the mixture continuously.

Thereafter, the capsules can be isolated, for example by spray-drying.

The microcapsules thus prepared are applied in an amount of 4 g/qm to a carrier paper weighing 40 g/qm.

On combination with a customary receiving paper, red-violet written images are produced when an impression is made.

EXAMPLE 5

2 g of the colour-forming agent described in Example 3 are dissolved in 48 g of dibutyl phthalate at 60°-70° C. If the further procedure followed is as in Example 4, on combination with a customary receiving paper, black written images are obtained when an impression is made.

EXAMPLE 6

2 g of the colour-forming agent described in Example 2 are dissolved in 48 g of dimethylnapthalene at 60°-70° C. If the further procedure followed is as in Example 4, on combination with a customary receiving paper, blue written images are obtained when an impression is made.

EXAMPLE 7

2 g of the colour-forming agent given in line 8 of the table on page 12 are dissolved in 48 g of dimethylnaphthalene at 60°-70° C. If the further procedure followed is as in Example 4, on combination with a receiving paper, red written images are obtained when an impression is made.

EXAMPLE 8

A dispersion of 1 g of the carbinol ether described in Example 2 and 55 g of an aqueous 8% strength polyvinyl alcohol solution is prepared in a ball mill.

A second dispersion contains 80 g of 2,2-bis-(4-hydroxyphenyl)-propane and 450 g of an aqueous 8% strength polyvinyl alcohol solution.

The dispersion of the colour-forming agent is mixed with that of the developer in the ratio 1:20 and this mixture is applied to a sheet. Using a heated pen, blue writing is obtained on the dried sheet. 

We claim:
 1. Pressure-sensitive recording material, characterised in that it contains a substrate coated with an acidic color developer and a substrate coated with a colour-forming agent of the formula ##STR35## wherein R₁ denotes hydrogen or a non-ionic radical which is free from amino groups,R₂ denotes hydroxyl, alkylamino, dialkylamino, acylamino, aralkylamino, arylamino, a saturated heterocyclic radical, alkoxy, alkenyloxy, aralkoxy, cycloalkoxy, aryloxy, acyloxy or a direct bond to R₄, R₃ denotes hydroxyl, alkoxy, aralkoxy, alkenyloxy, cycloalkoxy, aryloxy, alkylthio, arylthio or a radical of the formula ##STR36## R₅ and R₆ independently of one another denote hydrogen, alkyl, aralkyl, cycloalkyl or aryl or, together with the nitrogen atom, form a ring, or R₅ forms a ring with the ring B in the o-position relative to the nitrogen atom, and R₄ denotes an aryl radical which is free from amino groups or a heterocyclic radical, and further rings can be fused to the rings A, B and R₄ and the cyclic and acylic radicals and the rings A and B can contain non-ionic substituents, said color forming agent being dissolved or dispersed in a non-volatile organic solvent.
 2. Recording material according to claim 1, characterised in that it contains a colour-forming agent of the formula ##STR37## wherein R₁ ' denotes hydrogen; hydroxyl; C₁ -C₆ -alkoxy; C₂ -C₆ -alkenyloxy; cyclohexyloxy; cyclopentyloxy; benzyloxy, phenylethoxy, phenyloxy, naphthyloxy, phenylthio or naphthylthio which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; or C₁ -C₆ -alkylthio,R₂ ' denotes hydroxyl; C₁ -C₁₂ -alkyl- or dialkylamino; C₁ -C₄ -alkylcarbonylamino; benzylamino, phenylethylamino, phenylamino, naphthylamino, phenylsulphonylamino or benzoylamino which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; morpholino, piperidino or pyrrolidino which are optionally substituted by C₁ -C₄ -alkyl; C₁ -C₁₂ -alkoxy; C₂ -C₁₂ -alkenyloxy; C₁ -C₄ -alkoxycarbonyloxy; benzyloxy, phenylethoxy, phenyloxy, naphthyloxy, benzoyloxy, phenylsulphonyloxy or phenylsulphinyloxy which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; cyclohexyloxy; cyclopentyloxy or a direct bond to R₄ ', R₃ ' denotes hydroxyl; C₁ -C₆ -alkoxy; C₂ -C₆ -alkenyloxy, cyclohexyloxy; cyclopentyloxy; benzyloxy, phenylethoxy, phenyloxy, naphthyloxy, phenylthio or naphthylthio which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; C₁ -C₆ -alkylthio or a radical of the formula ##STR38## R₅ ' and R₆ ' independently of one another denote hydrogen; C₁ -C₆ -alkyl which is optionally substituted by C₁ -C₄ -alkoxy, C₁ -C₄ -alkylcarbonyloxy, hydroxyl, halogen or cyano; benzyl, phenylethyl, phenyl or naphthyl which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; cyclopentyl or cyclohexyl, or R₅ ' and R₆ ', together with the nitrogen atom, denote a pyrrolidine, pyrazoline, piperidine or morpholine ring or, R₅ ', together with the nitrogen atom and ring B, denotes an indoline or tetrahydroquinoline ring, it being possible for the rings mentioned to be substituted by methyl or phenyl, R₄ ' denotes a radical of the formula ##STR39## in which m=1-4 and R₈ =hydrogen, C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy; halogen; carboxamide; sulphonamide; cyano; nitro; halogen; C₁ -C₄ -alkylthio; C₁ -C₄ -alkylsulphonyl; C₁ -C₄ -alkylcarbonyl; C₁ -C₄ -alkoxycarbonyl; or benzyl, phenylethyl, benzyloxy, phenylethoxy, phenyloxy, cyclopentyloxy, cyclohexyloxy, phenylthio, benzylsulphonyl, phenylethylsulphonyl or phenylsulphonyl which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen, or R₄ ' denotes an indole, triazole, furane, thiophene, pyridine, pyrazolone, thiazine, oxazine, benzothiophene, indazole, benzothiazole, quinoline, phenothiazine and phenoxazine radical, which in turn can be substituted by 1-2 radicals, such asC₁ -C₆ -alkyl, phenyl, benzyl or C₁ -C₄ -alkoxy which are optionally substituted by C₁ -C₄ -alkoxy, cyano or halogen, R₇ and R₇ ' denote hydrogen, C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, halogen or nitro and n and n' denote 1-4, andwherein the rings A and B can be fused, in the 2,3-position, to a benzene ring.
 3. Recording material according to claim 2, characterised in that it contains a colour-forming agent of the formula ##STR40## wherein R₁ " represents hydroxyl; C₁ -C₄ -alkoxy; C₁ -C₄ -alkylthio; cyclohexyloxy; cyclopentyloxy; or benzyloxy, phenylethoxy, phenyloxy, naphthyloxy, phenylthio or naphthylthio which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen,R₄ " represents a radical of the formula ##STR41## and,
 4. Recording material according to claim 2, characterised in that it contains a colour-forming agent of the formula ##STR42## wherein R₅ " and R₆ " independently of one another denotes hydrogen; C₁ -C₄ -alkyl; cyanoethyl; hydroxyethyl; acetoxyethyl; C₁ -C₄ -alkoxyethyl; or benzyl or phenyl which are optionally substituted by methyl, ethyl, methoxy or ethoxy, orR₅ " and R₆ ", together with the nitrogen atom, form a pyrrolidine, piperidine, morpholine, pyrazoline or piperazine ring which is optionally substituted by methyl and/or phenyl, R₉ and R₉ ' represents hydrogen, methyl, ethyl, methoxy, ethoxy or chlorine, or R₅ " and R₉ ', together with ring B and the nitrogen atom, form an indoline or tetrahydroquinoline ring which is optionally substituted by C₁ -C₄ -alkyl.
 5. Recording material according to claim 1 characterized in that it contains a colour-forming agent of the formula ##STR43## wherein R₁ ' denotes hydrogen; hydroxyl; C₁ -C₆ -alkoxy; C₂ -C₆ -alkenyloxy, cyclohexyloxy, cyclopentyloxy; benzyloxy, phenylethoxy, phenyloxy, naphthyloxy, phenylthio or naphthylthio which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; or C₁ -C₆ -alkylthio,R₂ ' denotes hydroxyl; C₁ -C₁₂ -alkyl- or dialkylamino; C₁ -C₄ -alkylcarbonylamino; benzylamino, phenylethylamino, phenylamino, naphthylamino, phenylsulphonylamino or benzoylamino which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; morpholino, piperidino or pyrrolidino which are optionally substituted by C₁ -C₄ -alkyl; C₁ -C₁₂ -alkoxy; C₂ -C₁₂ -alkenyloxy; C₁ -C₄ -alkoxycarbonyloxy; benzyloxy, phenylethoxy, phenyloxy, naphthyloxy, benzoyloxy, phenylsulphonyloxy or phenylsulphinyloxy which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; cyclohexyloxy; cyclopentyloxy or a direct bond to the indole radical bearing the R₁₃ and R₁₄ substituents. R₃ ' denotes hydroxyl; C₁ -C₆ -alkoxy; C₂ -C₆ -alkenyloxy, cyclohexyloxy; cyclopentyloxy; benxyloxy, phenylethoxy, phenyloxy, naphthyloxy, phenylthio or naphthylthio which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; C₁ -C₆ -alkylthio or a radical of the formula ##STR44## R₅ ' and R₆ ' independently of one another denote hydrogen; C₁ -C₆ -alkyl which is optionally substituted by C₁ -C₄ -alkoxy, C₁ -C₄ -alkylcarbonyloxy, hydroxyl, haogen or cyano; benzyl, phenylethyl, phenyl or naphthyl which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; cyclopentyl or cyclohexyl, or R₅ ' and R₆ ', together with the nitrogen atom, denote a pyrrolidine, pyrazoline, piperidine or morpholine ring, or, R₅ ', together with the nitrogen atom and ring B, denotes an indoline or tetrahydroquinoline ring, it being possible for the rings mentioned to be substituted by methyl or phenyl, R₇ and R₇ ' denote hydrogen, C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, halogen or nitro, R₉ represents hydrogen, methyl, ethyl, methoxy, ethoxy or chlorine, or R₁₃ represents C₁ -C₄ -alkyl or phenyl and R₁₄ represents hydrogen; C₁ -C₂₂ -alkyl which is optionally substituted by cyano, chlorine or hydroxyl; C₂ -C₄ -alkenyl; cyclohexyl; or phenyl or benzyl which are optionally substituted by methyl, ethyl, methoxy, ethoxy or chlorine, and the rings A and B can be fused, in the 2,3-position, to a benzene ring.
 6. Recording material, according to claim 5 characterised in that it contains a colour-forming agent of the formula ##STR45## wherein R₅ " and R₆ " independently of one another denotes hydrogen; C₁ -C₄ -alkyl; cyanoethyl; hydroxyethyl; acetoxyethyl; C₁ -C₄ -alkoxyethyl; or benzyl or phenyl which are optionally substituted by methyl, ethyl, methoxy or ethoxy, or R₅ " and R₆ ", together with the nitrogen atom, form a pyrrolidine, piperidine, morpholine, pyrazoline or piperazine ring which is optionally substituted by methyl and/or phenyl,R₈ = hydrogen, C₁ -C₄ -alkyl or C₁ -C₄ alkoxy; halogen; carboxamide; sulphonamide; cyano; nitro; halogen; C₁ l -C₄ -alkylthio; C₁ -C₄ -alkylsulphonyl; C₁ -C₄ -alkylcarbonyl; C₁ -C₄ -alkoxycarbonyl; or benzyl, phenylethyl, benzyloxy, phenylethoxy, phenyloxy, cyclopentyloxy, cyclohexyloxy, phenylthio, benzylsulphonyl, phenylethylsulphonyl or phenylsulphonyl which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen, R₉ and R₉ ' represents hydrogen, methyl, ethyl, methoxy, ethoxy or chlorine, or R₅ " and R₉ ", together with ring B and the nitrogen atom, form an indoline or tetrahydroquinoline ring which is optionally substituted by C₁ -C₄ -alkyl, R₁₃ ' represents methyl, ethyl or phenyl and R₁₄ ' represents hydrogen or C₁ -C₄ -alkyl.
 7. Recording material according to claim 1, characterized in that it contains a colour-forming agent of the formula ##STR46## R_(1') denotes hydrogen; hydroxyl; C₁ -C₆ -alkoxy; C₂ -C₆ -alkenyloxy; cyclohexyloxy; cyclopentyloxy; benzyloxy, phenylethoxy, phenyloxy, naphthyloxy, phenylthio or naphthylthio which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; or C₁ -C₆ -alkylthio,R₃ ' denotes hydroxyl; C₁ -C₆ -alkoxy; C₂ -C₆ -alkenyloxy, cyclohexyloxy; cyclopentyloxy; benzyloxy, phenylethoxy, phenyloxy, naphthyloxy, phenylthio or naphthylthio which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; C₁ -C₆ -alkylthio or a radical of the formula ##STR47## R₅ ' and R₆ ' independently of one another denote hydrogen; C₁ -C₆ -alkyl which is optionally substituted by C₁ -C₄ -alkoxy, C₁ -C₄ -alkylcarbonyloxy, hydroxyl, halogen or cyano; benzyl, phenylethyl, phenyl or naphthyl which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen; cyclopentyl or cyclohexyl, or R₅ ' and R₆ ', together with the nitrogen atom, denote a pyrrolidine, pyrazoline, piperidine or morpholine R₇ and R₇ ' denote hydrogen, C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, halogen or nitro, n and n' denote 1-4, R₉ represents hydrogen, methyl, ethyl, methoxy, ethoxy or chlorine, and R₁₃ represents C₁ -C₄ -alkyl or phenyl.
 8. Recording material according to claim 7, characterized in that it contains a colour-forming agent of the formula ##STR48## wherein R₅ " and R₆ " independently of one another denotes hydrogen; C₁ -C₄ -alkyl; cyanoetyl; hydroxyethyl; acetoxyethyl; C₁ -C₄ -alkoxyethyl; or benzyl or phenyl which are optionally substituted by methyl, ethyl, methoxy or ethoxy, orR₅ " and R₆ ", together with the nitrogen atom, form a pyrrolidine, piperidine, morpholine, pyrazoline or piperazine ring which is optionally substituted by methyl and/or phenyl, R₈ = hydrogen, C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy, halogen; carboxamide; sulphonamide; cyano; nitro; halogen; C₁ -C₄ -alkylthio; C₁ -C₄ -alkylsulphonyl; C₁ -C₄ -alkylcarbonyl; C₁ -C₄ -alkoxycarbonyl; or benzyl, phenylethyl, benzyloxy, phenylethoxy, phenyloxy, cyclopentyloxy, cyclohexyloxy, phenylthio, benzylsulphonyl, phenylethylsulphonyl or phenylsulphonyl which are optionally substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen, or R₉ ' represents hydrogen, methyl, ethyl methoxy, ethoxy or chlorine, R₅ " and R₉ ', together with ring B and the nitrogen atom, form an indoline or tetrahydroquinoline ring which is optionally substituted by C₁ -C₄ -alkyl, and R₁₃ ' represents methyl, ethyl or phenyl.
 9. Recording material according to claim 6, characterized in that R₈ represents methyl, hydrogen, phenyloxy, benzyloxy or C₁ -C₄ -alkoxy.
 10. Recording material according to claim 8, characterized in that R₈ represents methyl, hydrogen, phenoxy, benzyloxy or C₁ -C₄ -alkoxy. 